Comparison of the Effects of Temperature and Dehydration Mode on Glycerin-Based Approaches to SMILE-Derived Lenticule Preservation

Purpose: The aim of this study was to explore the optimal method of small-incision lenticule extraction (SMILE)-derived lenticules, subjected to long-term preservation using glycerol, under a range of temperatures, and using an array of dehydration agents. Methods: In total, 108 myopic lenticules were collected from patients undergoing the SMILE procedure. Fresh lenticules served as a control group for this study, whereas all other lenticules were separated into 8 groups, which were preserved at 4 different temperatures (room temperature [RT], 4, -20, and -80 degrees C) with or without silica gel in anhydrous glycerol. Evaluated parameters included thickness, transmittance, hematoxylin and eosin staining, transmission electron microscopy, and immunohistochemistry analyses. Results: After a 3-month preservation period, lenticular thickness in these different groups was significantly increased, particularly for samples stored at RT. The mean percentage transmittance of lenticules stored at -80 degrees C with or without silica gel was closest to that of fresh lenticules. Hematoxylin and eosin staining revealed sparsely arranged collagen fibers that were more scattered in preserved lenticules relative to fresh lenticules, particularly in RT samples. Transmission electron microscopy revealed that the fibril bundles densities in lenticules stored at RT were significantly less than those stored at other temperatures. Immunohistochemistry analyses revealed reductions in or loss of CD45 and human leukocyte antigens in all preserved lenticules relative to control samples. Conclusions: Of the tested approaches, the preservation of SMILE-derived lenticules over a 3-month period was optimal at -80 degrees C with or without silica gel in anhydrous glycerol.